Oil: it's all the same

API is but one standard, and not all manufacturers use it.

Lots has changed in 10 years, use oil that meets the vehicle's manufacturers specification.

So, no, all oil is not the same.

It's not all the same.... try cooking with it. The food just doesn't taste as good as when using EVOO..... :0)

While I have no problem using different brands of oil from one oil change to another, please remember that most people believe that a good percentage of your engine wear occurs at startup. Most taxi cabs run all day long or at least never let the engine cool down.

I also believe that conventional oils have made huge improvements in the last 10 years and I think your test would have more validity if it wasn't so old.

BS!

It is NOT all the same unless one is anal, smart-if you prefer, enough to strictly follow all recommended maintenance procedures.

you can beleive what you want... go out and buy several cases of Pennzoil, and drive your car to 200,000. And let us know.

Thanks for the heads up, now I know why my french fries don't taste the same the ones at the dinner :))

Thanks for informing me that a valid scientific test is BS

Do you have evidence to the contrary ?

Nobody said the test is BS. It is, however, old and outdated, and somewhat flawed in it's original form. MUCH has changed in lubrication science in the intervening 10 years, and as pointed out, Taxi service is hardly representative of most daily driving. You are free to believe whatever you care to believe, and the last poster's suggestion that you buy a couple cases of Pennzoil and attempt to get 200,000 miles (or even Km) out of your engine on it is good advice if you truly believe the published test.

As for evidence, how's 37 years' experience? From a professional auto mechanic?

What I do believe is that the test results although 10 years old show that at that time there was no significant difference in the performance of the products tested.

Is a test using NYC taxicabs the same as testing under the conditions that you or I drive under, NO it is not. However until someone can point to a valid scientific test under different conditions that more accurately reflect everyday driving conditions I will believe the results of the published test as being valid and accurate.

Anecdotal evidence of a single automotive technician even with 50 years experience is just that, nonscientific and one mans stories.

In the 10 years that have passed since the test much has changed in lubrication science. That being stipulated I am sure that none of the motor oil producers has made their product lower in quality, but on the contrary has improved their product.

Just a few personal experiences - from years past so may not be valid today.

I used Quaker State's top line oil (supreme??) in my '63 valiant six antil I had reason to pull the engine down for repairs. The engine was clean as a whip except - it was totally coated with a waxy substance that was so thick in places I was afraid it could restrict lubrication. May not have been a problem, but I've not seen that with any other oil.

1970 Toyota 1200, never had a problem until little brother took it to a lubeshop and got cheap 10w30 oil change. Less than a week later the oil light came on. No problem, says I, the "oil pisser switch" has failed - normal occurrence - so I replaced the switch. Oil light still on. Changed the oil to Castrol, which I had been using previously, and no more problems. The problem oil was ESSO's cheapest, in a green can at the time.

1986 Dodge Caravan, just off warrantee. I had to deliver some parts. The oil had just been changed at a Pennzoil quick-lube. Less than 50 miles from home, the oil light came on at cruise. Went off at idle. Kept getting worse, and at about 65 or 70 miles I called back to the office to see what had been done service-wise. When I found out, I went to the closest oil change outlet - a Castrol place, and had the oil changed, with Castrol GTX. Never had another problem. The "tech" that dropped the oil said it was thin as water.

That's TWO very premature loss of viscosity occurrences that I've been involved with on vehicles I had direct personal experience with - and there were dozens more on customer's vehicles.

The was buildup on the Valiant may not have been a problem, but I was unwilling to find out.

There is a LOT of difference in quality between oils. Sadly, you cannot predict by manufacturer's name, or price, but there ARE some brands that I have learned IO can depend on, and some I choose not to trust. I also NEVER use the lowest price product from any company.

Your experiences are duly noted and I accept them to be truthful.

I have had a number of automobiles in my 51 years of owning autos, some with mileage as high as 180,000 miles on them. I have never experienced an engine failure or major problem that was lubrication related. Other problems galore but nothing attributable lubrication.

This of course does not include the crappie oil lines on my 2001 GMC Jimmy, but I can't blame the oil for that, just crappie GM design, engineering and quality control.

generally I agree. The study is a lot better than NO study or some techs observations. I think its safe to say that any modern motor oil is perfectly capable of lubricating MOST engines beyond 100k miles or even alot more. If changed when it needs it of coarse. And to say that study isn't valid because its old is IMO stupid because oil formulations get better over time, not worse, ya know? :) It makes me think of all the people that don't keep a car over about 2 years anyway, why even change it all all? :)

180,000miles? Those are just pups!! When you get over 250,000 miles, you are getting into "high mileage". Heck, I got over 214,000 miles on a 61 Austin/Morris Mini 850 - with a rebuild (new rings, bearings and gaskets - no rebore or crank grinding -) at about 200,000 miles. The most common lubrication related failures have historically been valve lifters, cam lobe wear, timing chains and tensioners, cyl wear, and crankshaft bearings, in roughly that order. A lot of lubrication related failures are also attributable to engine overheating (sometimes seen as a result, other times seen as a cause). This is particularly true of cyl wear, and to a lesser extent, bearing failures. CURRENT lubrication failure modes lean more to "coking" issues where oil flow is restricted by deposit buildup, and glycol contamination where bearings are heading south very quickly after leaky intake manifold gaskets, etc. let antifreeze, even in relatively minute quantities, into the crankcase. These are also often seen/regarded as engine temperature related failures.

The engines only ran 60,000 mi, which is not that far. I wonder if the differences in mass of the bearings and the wear and tear were obscured by differences in the tolerances when the engines were built.

You would really need to test the engines at like 200,000 mi.

Jeff

For consistency, we used only 1992-93 Chevrolet Caprice cabs. Each received a precisely rebuilt 4.3-liter V6 at the beginning of its 60,000-mile test. We started with six rebuilt engines; after each engine was installed in a cab, the six engines that were removed were rebuilt and installed in six other cabs-and so on. Using that rotation, we monitored 75 cabs over 4-1/2 million miles of driving in New York City and its environs. Each oil was tested in three engines. A local shop completely machined each engine block and crankshaft, rebuilt the cylinder heads, and installed new bearings, pistons, rings, seals, gaskets, and oil pump. Though the engines originally had roller lifters and camshafts, a design that reduces friction, we installed conventional sliding lifters and camshafts to accelerate wear.

Before the engines were assembled, we measured or weighed the parts most likely to show wear if the oil wasn't doing its job - the camshafts, valve lifters, and connecting-rod bearings. Each cab went through a break-in procedure before hitting the road. During testing, two engine timers measured the time the engine was running and the time it was in gear.

Over the next 22 months, our engineers paid more than 100 calls - usually without notice - on the fleet garage. They dropped off test oil and picked up used-oil samples for ongoing analysis. They also made sure that oil was being added to the engines when necessary and changed as scheduled.

After each 60,000-mile test, we remeasured the key engine parts. We also examined combustion-chamber deposits, the color of the valves, scoring of cylinder walls, and valve-deck deposits for any sign of engine problems.

After each engine ran about 60,000 miles (and through 10 months of seasonal changes), we disassembled it and measured the wear on the camshaft, valve lifters, and connecting-rod bearings. We used a tool precise to within

0.00001 inch to measure wear on the key surfaces of the camshaft, and a tool precise to within 0.0001 inch on the valve lifters. The combined wear for both parts averaged only 0.0026 inch, about the thickness of this magazine page. Generally, we noted as much variation between engines using the same oil as between those using different oils. Even the engines with the most wear didn't reach a level where we could detect operational problems.

We measured wear on connecting rod bearings by weighing them to the nearest

0.0001 gram. Wear on the key surface of each bearing averaged 0.240 gram - about the weight of seven staples. Again, all the tested oils provided adequate protection.

Under the cars and conditions of the test... some cars today now specify oil ratings other than those that the API puts out. This might be more important if the car also specifies a longer oil change interval.